The disclosure pertains to a pipe-like hollow article made of ultra-high molecular weight polyethylene (UHMWPE) tapes and a thermoplastic and/or thermoplastic elastomer, whereby the tapes are wound to create said article.
Hollow articles made of UHMWPE are known in the art.
In EP 0 223 252, a method for preparing a molded article of UHMWPE is disclosed. A thin-wall UHMWPE porous sheet is molded into a thin-wall article, whereby the porous sheet is prepared by feeding UHMWPE powder to between at least two heated rolls and melting it into a sheet at molding temperature more than 140° C. For producing the molded article a temperature in the range of more than 150° C. is used for melting the UHMWPE. The applied tapes have a low tensile strength and low modulus and thus also the article has a low dimensional stability.
In WO 2012/097083, a method for manufacturing ballistic helmets is disclosed. For the helmet Tensylon or Dyneema is used, whereby this ballistic-tolerant tape has been coated with a thermoplastic or thermosetting adhesive and is wound around a solid mandrel. The winding results in a spheroid structure, which can be cut into two equally-spaced preforms. Although the winding angles and sequences of the winding machine used in this process may be changed, the hollow article of this document is always spheroid.
In EP 0 803 347, an improved coating for e.g., fabrics for tanks is disclosed. This coating has an improved resistance to permeation of aromatics and mineral acids and resistance to bend cracking. To achieve this, ultra-high molecular weight polyethylene tapes are used, whereby all tapes are helically wounded on a core to create the article. This document does not disclose the use of tapes with a tensile strength of greater than 1.5 GPa according to ASTM D882-00 and an modulus of greater than 100 GPa according to ASTM D882-00 and a 200/110 uniplanar orientation parameter of at least 3. In addition, EP 0 803 347 does not disclose that the main extension direction of at least half of the tapes in the article is in an angle of 20 to 100° with regard to the main extension direction of the article, whereby also the 200/120 uniplanar orientation parameter of these tapes is parallel to the main extension direction of these tapes. Burst pressure and advantages of wound technics for the tapes are not discussed in this document.
EP 2 307 180 discloses ultra-high molecular weight polyethylene tapes, whereby the tapes have a tensile strength of greater than 1.5 GPa according to ASTM D882-00 and an modulus of greater than 100 GPa according to ASTM D882-00 and a 200/110 uniplanar orientation parameter of at least 3. This document does not disclose the use of such tapes for pipe-like articles and no arrangement of tapes in articles is discussed. In addition, EP 2 307 180 gives no hints in respect of an arrangement of such tapes in an article for increasing the burst pressure for such an article.